<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta http-equiv="X-UA-Compatible" content="ie=edge" />
    <title>Document</title>
    <script src="./lib/vue-2.4.0.js"></script>
    <style>
      .v-enter,
      .v-leave-to {
        opacity: 0;
        transform: translateX(150px);
      }
      .v-enter-active,
      .v-leave-active {
        transition: all 0.8s ease;
      }
    </style>
  </head>

  <body>
    <div id="app">
      <input type="button" value="toggle" @click="flag=!flag" />
      <!-- 需求： 点击按钮，让 h3 显示，再点击，让 h3 隐藏 -->
      <transition>
        <h3 v-if="flag">这是一个H3</h3>
      </transition>
    </div>

    <script>
      var vm = new Vue({
        el: "#app",
        data: {
          flag: false
        },
        methods: {}
      });
    </script>
  </body>
</html>
